1809920820 has 24 divisors (see below), whose sum is σ = 5067778464. Its totient is φ = 482645536.

The previous prime is 1809920809. The next prime is 1809920831. The reversal of 1809920820 is 280299081.

It is an interprime number because it is at equal distance from previous prime (1809920809) and next prime (1809920831).

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15082614 + ... + 15082733.

It is an arithmetic number, because the mean of its divisors is an integer number (211157436).

Almost surely, 2^1809920820 is an apocalyptic number.

1809920820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1809920820 is an abundant number, since it is smaller than the sum of its proper divisors (3257857644).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1809920820 is a wasteful number, since it uses less digits than its factorization.

1809920820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30165359 (or 30165357 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 1809920820 is about 42543.1641982587. The cubic root of 1809920820 is about 1218.6711366195.

The spelling of 1809920820 in words is "one billion, eight hundred nine million, nine hundred twenty thousand, eight hundred twenty".